HAMPSTEAD, N.H. — Scott Brown, former US senator, took a swipe Monday at his onetime colleague from New Hampshire, US Senator Jeanne Shaheen, calling the Democrat’s recent reference to his possibly trying to unseat her “shameful.”

Speaking to reporters Monday night outside a function hall, where Brown addressed Republicans at a fund-raiser for local candidates, he criticized Shaheen for raising the specter of a matchup between the two in a recent campaign e-mail. The fund-raiser was closed to the media.

“I think it’s shameful for her to do that, for one, because I’m not a declared candidate,” Brown said. “I think she should be addressing the government shutdown problem.”

Advertisement - Continue Reading Below

In an e-mail Friday to US Senator Elizabeth Warren’s campaign committee, a fellow Democrat who defeated Brown last year, Shaheen wrote that Brown’s visit to Hampstead was his seventh meeting with New Hampshire Republicans in the last six months.

But a spokesman for the New Hampshire Democratic Party fired back at Brown, whom he called an ally of “big oil and Wall Street.”

“Scott Brown is dreaming if he thinks New Hampshire wants to send him and his special interest agenda to the Senate,” spokesman Harrell Kirstein said in a statement.

Brown, who arrived in a dented GMC pickup truck, did not say if he plans to run for office again, despite rumors of a possible Senate bid in New Hampshire or even a presidential run.

Brown and his wife recently put their Wrentham home on the market and own a vacation residence in the Granite State. He did say, however, that he plans to continue traveling around the country to help raise funds for other Republicans. “I’m pretty active,” he said. “I don’t know how much more active I can get.”

He described the GOP as a “big idea party” that has room for Tea Party-backed lawmakers such as Senators Rand Paul and Ted Cruz, but also more moderate figures like himself.

His visits to New Hampshire and Iowa, two key presidential primary states, have prompted some political observers to raise the possibility of Brown launching a bid for the White House or perhaps for Shaheen’s seat.

Brown announced in August that he will not run for governor in Massachusetts in 2014. He has not ruled out another run for elective office, but has also made no definitive statements about what job he may pursue.

He demurred when asked Monday if he was closer to making a decision.

“I’m doing exactly what I said I was going to do,” Brown said, “which is traveling around the country helping other committees, individuals, and groups raise money and raise awareness and try to get my message of problem solving.”

His remarks came hours after the Massachusetts GOP filed an ethics complaint against Warren’s chief of staff, alleging that the top aide sent a fund-raising e-mail on government time that mentioned Brown’s possibly running against Shaheen.

According to the complaint filed with the Senate Select Committee on Ethics, Mindy Myers, Warren’s chief of staff, sent an e-mail from a campaign account affiliated with her boss on Friday afternoon, while the Senate was in session.

The message urged Warren supporters to donate to the campaign fund of Shaheen and included the rallying cry, “Let’s show Scott Brown: If he decides to run against Jeanne Shaheen, we’ll be there once again to stop him.”

Rob Cunningham, executive director of the Massachusetts GOP, wrote in a letter to the ethics committee that Myers violated campaign finance laws because she sent the message from “what appears to be a government office” while she was being paid with taxpayer dollars.

“The attached communication makes clear, and an investigation will no doubt confirm, that there is a reason to believe that Mindy Myers has participated in partisan campaign fund-raising activity” in violation of applicable laws, Cunningham wrote. Myers, who managed Warren’s 2012 Senate campaign, could not be reached for comment.

Warren’s office said in a brief statement that the campaign e-mail was sent by a private vendor and that no government resources were used. The statement also said Myers is a political fund designee.

Such designees are permitted to raise money for Senate campaigns, said Marc E. Elias, a Democratic lawyer in Washington who handles campaign finance and government ethics cases. He is not representing Myers or Warren.

But Jennifer Horn, who chairs the New Hampshire Republican State Committee, blasted Shaheen in a statement for focusing “on raising campaign cash instead of serving the people of New Hampshire.”